diff --git a/lib/vagrant-hostmanager/hosts_file.rb b/lib/vagrant-hostmanager/hosts_file.rb
index 582ba53..7c4ac8f 100644
--- a/lib/vagrant-hostmanager/hosts_file.rb
+++ b/lib/vagrant-hostmanager/hosts_file.rb
@@ -10,7 +10,11 @@ module VagrantPlugins
           realhostfile = '/etc/inet/hosts'
           move_cmd = 'mv'
         elsif (machine.communicate.test("test -d $Env:SystemRoot"))
-          realhostfile = "#{ENV['WINDIR']}\\System32\\drivers\\etc\\hosts"
+          windir = ""
+          machine.communicate.execute("echo %SYSTEMROOT%", {:shell => :cmd}) do |type, contents|
+            windir << contents.gsub("\r\n", '') if type == :stdout
+          end
+          realhostfile = "#{windir}\\System32\\drivers\\etc\\hosts"
           move_cmd = 'mv -force'
         else 
           realhostfile = '/etc/hosts'